Radiolytic and thermal dechlorination of organic chlorides adsorbed on molecular sieve 13X.

Reductive dechlorination of chlorobenzene (PhCl), trichloroethylene (TCE), tetrachloroethylene (PCE), 1- and 2-chlorobutanes, chloroform, carbon tetrachloride, and 1,1,1- and 1,1,2-trichloroethanes adsorbed on molecular sieve 13X was investigated. The molecular sieve adsorbing the organic chlorides was irradiated with gamma-rays, heated, or allowed to stand at room temperature in a sealed ampule and was then soaked in water. The dechlorination yields were determined from the Cl- concentrations of the supernatant aqueous solutions. It was found that the chlorinated alkanes adsorbed on the molecular sieve are readily dechlorinated on standing at room temperature. The dechlorination at room temperature was limited for TCE and PCE. PhCl was quite stable even at 200 degrees C. gamma-Radiolysis was examined for PhCl, TCE, and PCE at room temperature. The radiation chemical yields of the dechlorination, G(Cl-), were 1.9, 40, and 30 for PhCl, TCE, and PCE, respectively. After 5 h of heating at 200 degrees C, the dechlorination yields for TCE and PCE were 24.5 and 4.3%, respectively. TCE is much more reactive than PCE in the thermal dechlorination, whereas their radiolytic dechlorination yields are comparable. The pH of the supernatant solutions decreased along with the dechlorination.